From 8b5dcb4c2175ac706a4e1c34ce83301213800689 Mon Sep 17 00:00:00 2001

From: Jan Kratochvil <jan.kratochvil@redhat.com>

Date: Mon, 18 Jan 2021 22:56:53 +0100

Subject: [PATCH 5/6] debugedit: Implement DWARF-5 unit header and new forms

 parsing.

Recognize the various new DWARF5 .debug sections.

Parse and skip new DWARF5 forms in read_abbrev and skip_form.

Read DWARF5 unit headers for compile and partial units in edit_info.

This is enough to be able to process gcc -gdwarf-5 produced binaries

without the new DWARF5 .debug_line format (which isn't produced with

binutils < 2.36).

Patches slightly edited/merged by Mark Wielaard <mark@klomp.org>

---

 tools/debugedit.c | 88 +++++++++++++++++++++++++++++++++++++++++++----

 1 file changed, 81 insertions(+), 7 deletions(-)

diff --git a/tools/debugedit.c b/tools/debugedit.c

index 7464883c5..be5fee85b 100644

--- a/tools/debugedit.c

+++ b/tools/debugedit.c

@@ -453,6 +453,11 @@ static debug_section debug_sections[] =

 #define DEBUG_TYPES	11

 #define DEBUG_MACRO	12

 #define DEBUG_GDB_SCRIPT	13

+#define DEBUG_RNGLISTS	14

+#define DEBUG_LINE_STR	15

+#define DEBUG_ADDR	16

+#define DEBUG_STR_OFFSETS	17

+#define DEBUG_LOCLISTS	18

     { ".debug_info", NULL, NULL, 0, 0, 0 },

     { ".debug_abbrev", NULL, NULL, 0, 0, 0 },

     { ".debug_line", NULL, NULL, 0, 0, 0 },

@@ -467,6 +472,11 @@ static debug_section debug_sections[] =

     { ".debug_types", NULL, NULL, 0, 0, 0 },

     { ".debug_macro", NULL, NULL, 0, 0, 0 },

     { ".debug_gdb_scripts", NULL, NULL, 0, 0, 0 },

+    { ".debug_rnglists", NULL, NULL, 0, 0, 0 },

+    { ".debug_line_str", NULL, NULL, 0, 0, 0 },

+    { ".debug_addr", NULL, NULL, 0, 0, 0 },

+    { ".debug_str_offsets", NULL, NULL, 0, 0, 0 },

+    { ".debug_loclists", NULL, NULL, 0, 0, 0 },

     { NULL, NULL, NULL, 0, 0, 0 }

   };

@@ -755,12 +765,28 @@ no_memory:

 	    }

 	  form = read_uleb128 (ptr);

 	  if (form == 2

-	      || (form > DW_FORM_flag_present && form != DW_FORM_ref_sig8))

+	      || (form > DW_FORM_flag_present

+		  && !(form == DW_FORM_ref_sig8

+		       || form == DW_FORM_data16

+		       || form == DW_FORM_implicit_const

+		       || form == DW_FORM_addrx

+		       || form == DW_FORM_loclistx

+		       || form == DW_FORM_rnglistx

+		       || form == DW_FORM_addrx1

+		       || form == DW_FORM_addrx2

+		       || form == DW_FORM_addrx3

+		       || form == DW_FORM_addrx4)))

 	    {

-	      error (0, 0, "%s: Unknown DWARF DW_FORM_%d", dso->filename, form);

+	      error (0, 0, "%s: Unknown DWARF DW_FORM_0x%x", dso->filename,

+		     form);

 	      htab_delete (h);

 	      return NULL;

 	    }

+	  if (form == DW_FORM_implicit_const)

+	    {

+	      /* It is SLEB128 but the value is dropped anyway.  */

+	      read_uleb128 (ptr);

+	    }

 	  t->attr[t->nattr].attr = attr;

 	  t->attr[t->nattr++].form = form;

@@ -1505,6 +1531,7 @@ skip_form (DSO *dso, uint32_t *formp, unsigned char **ptrp)

 	*ptrp += 4;

       break;

     case DW_FORM_flag_present:

+    case DW_FORM_implicit_const:

       break;

     case DW_FORM_addr:

       *ptrp += ptr_size;

@@ -1512,14 +1539,24 @@ skip_form (DSO *dso, uint32_t *formp, unsigned char **ptrp)

     case DW_FORM_ref1:

     case DW_FORM_flag:

     case DW_FORM_data1:

+    case DW_FORM_strx1:

+    case DW_FORM_addrx1:

       ++*ptrp;

       break;

     case DW_FORM_ref2:

     case DW_FORM_data2:

+    case DW_FORM_strx2:

+    case DW_FORM_addrx2:

       *ptrp += 2;

       break;

+    case DW_FORM_strx3:

+    case DW_FORM_addrx3:

+      *ptrp += 3;

+      break;

     case DW_FORM_ref4:

     case DW_FORM_data4:

+    case DW_FORM_strx4:

+    case DW_FORM_addrx4:

     case DW_FORM_sec_offset:

       *ptrp += 4;

       break;

@@ -1528,12 +1565,20 @@ skip_form (DSO *dso, uint32_t *formp, unsigned char **ptrp)

     case DW_FORM_ref_sig8:

       *ptrp += 8;

       break;

+    case DW_FORM_data16:

+      *ptrp += 16;

+      break;

     case DW_FORM_sdata:

     case DW_FORM_ref_udata:

     case DW_FORM_udata:

+    case DW_FORM_strx:

+    case DW_FORM_loclistx:

+    case DW_FORM_rnglistx:

+    case DW_FORM_addrx:

       read_uleb128 (*ptrp);

       break;

     case DW_FORM_strp:

+    case DW_FORM_line_strp:

       *ptrp += 4;

       break;

     case DW_FORM_string:

@@ -1560,7 +1605,7 @@ skip_form (DSO *dso, uint32_t *formp, unsigned char **ptrp)

       assert (len < UINT_MAX);

       break;

     default:

-      error (0, 0, "%s: Unknown DWARF DW_FORM_%d", dso->filename, *formp);

+      error (0, 0, "%s: Unknown DWARF DW_FORM_0x%x", dso->filename, *formp);

       return FORM_ERROR;

     }

@@ -2030,7 +2075,10 @@ edit_info (DSO *dso, int phase, struct debug_section *sec)

   endsec = ptr + sec->size;

   while (ptr < endsec)

     {

-      if (ptr + (sec == &debug_sections[DEBUG_INFO] ? 11 : 23) > endsec)

+      unsigned char *cu_start = ptr;

+

+      /* header size, version, unit_type, ptr_size.  */

+      if (ptr + 4 + 2 + 1 + 1 > endsec)

 	{

 	  error (0, 0, "%s: %s CU header too small",

 		 dso->filename, sec->name);

@@ -2052,13 +2100,36 @@ edit_info (DSO *dso, int phase, struct debug_section *sec)

 	}

       cu_version = read_16 (ptr);

-      if (cu_version != 2 && cu_version != 3 && cu_version != 4)

+      if (cu_version != 2 && cu_version != 3 && cu_version != 4

+	  && cu_version != 5)

 	{

 	  error (0, 0, "%s: DWARF version %d unhandled", dso->filename,

 		 cu_version);

 	  return 1;

 	}

+      int cu_ptr_size = 0;

+

+      if (cu_version >= 5)

+	{

+	  uint8_t unit_type = read_8 (ptr);

+	  if (unit_type != DW_UT_compile && unit_type != DW_UT_partial)

+	    {

+	      error (0, 0, "%s: Unit type %u unhandled", dso->filename,

+		     unit_type);

+	      return 1;

+	    }

+

+	  cu_ptr_size = read_8 (ptr);

+	}

+

+      unsigned char *header_end = (cu_start + 23 + (cu_version < 5 ? 0 : 1));

+      if (header_end > endsec)

+	{

+	  error (0, 0, "%s: %s CU header too small", dso->filename, sec->name);

+	  return 1;

+	}

+

       value = read_32_relocated (ptr);

       if (value >= debug_sections[DEBUG_ABBREV].size)

 	{

@@ -2070,9 +2141,12 @@ edit_info (DSO *dso, int phase, struct debug_section *sec)

 	  return 1;

 	}

+      if (cu_version < 5)

+	cu_ptr_size = read_8 (ptr);

+

       if (ptr_size == 0)

 	{

-	  ptr_size = read_8 (ptr);

+	  ptr_size = cu_ptr_size;

 	  if (ptr_size != 4 && ptr_size != 8)

 	    {

 	      error (0, 0, "%s: Invalid DWARF pointer size %d",

@@ -2080,7 +2154,7 @@ edit_info (DSO *dso, int phase, struct debug_section *sec)

 	      return 1;

 	    }

 	}

-      else if (read_8 (ptr) != ptr_size)

+      else if (cu_ptr_size != ptr_size)

 	{

 	  error (0, 0, "%s: DWARF pointer size differs between CUs",

 		 dso->filename);

-- 

2.18.4